The design was based on the earlier Pollitt Class 9G 2-4-2T locomotives,[1] but with a lengthened boiler and a leading bogie to carry it.

[2] This extension of running gear also resembled an early Robinson design for the Irish Waterford, Limerick and Western Railway.

Some locomotives were rebuilt further as C13/3, with shortened chimneys and domes to fit within the LNER loading gauge.

[2] The 9K class was built for the London suburban services, running from the GCR's Marylebone terminus.

[2] From 1922 they were dispersed away from London through the GCR network, to South Yorkshire between Manchester, Sheffield and Mexborough.

The South Yorkshire engines gradually moved to Gorton locomotive shed, from where they were used on Manchester suburban services, and destinations as far as Hayfield and Macclesfield, later joined by the 9Ls, until they were both replaced by DMUs after post-1955 dieselisation.

[4] Coal capacity was also increased by raising the rear wall of the bunker with a semicircular extension.

[4] Water pick-up gear and shortened chimneys to fit the LNER loading gauge were removed and changed as for the 9K class.

[4] The 9L class was built for the London suburban services from Marylebone and they were based at Neasden shed.

With the introduction of the Class 9Ns, the 9Ls were moved to stopping services on the Great Central Main Line and by 1922 they were based around Nottingham, with one of the twelve stabled at Woodford and some occasional allocations to Hitchin and Hatfield.